1. Field of the Invention
The present invention relates to an apparatus for manufacturing an image display device, and more particularly, to a spray nozzle for use in the manufacture of an image display device and spraying apparatus using the same. Although the present invention is suitable for a wide scope of applications, it is particularly suitable for regulating an injection angle of fluid to be discharged from a spray nozzle during a spraying process, and a spraying apparatus using a spray nozzle.
2. Discussion of the Related Art
Recently, a variety of light and thin, flat panel display devices, which solve the weight and bulk problems of cathode ray tubes have attracted considerable attention. Accordingly, flat panel displays have been replacing cathode ray tubes. Examples of flat panel display devices include liquid crystal displays, field emission displays, plasma display panels, and light emitting displays.
Among the variety of flat panel display devices, liquid crystal displays are designed to display an image via a regulation of light transmissibility through liquid crystal molecules using an electric field. More specifically, a liquid crystal display includes a liquid crystal panel in which liquid crystal cells are arranged in a matrix form, and a drive circuit to drive the liquid crystal panel. The liquid crystal panel is provided with a common electrode and pixel electrodes to apply an electric field to each of the liquid crystal cells. Typically, the pixel electrodes are formed on a lower substrate at positions corresponding to the respective liquid crystal cells. The common electrode is integrally formed across the entire surface of an upper substrate. The pixel electrodes are connected to thin film transistors (hereinafter, referred to as “TFTs”), which are used as switching devices. The pixel electrodes are used to drive the liquid crystal cells, along with the common electrode, in accordance with data signals fed through the TFTs.
FIG. 1 is a cross-sectional view schematically illustrating a related art liquid crystal panel. As shown in FIG. 1, the related art liquid crystal panel includes a color filter array substrate 4 and a TFT array substrate 2 with liquid crystal molecules 52 filled in a gap between the color filter array substrate 4 and the TFT array substrate 2. The color filter array substrate has a black matrix 44, a color filter 46, an overcoat layer 47, a common electrode 48, and an upper alignment film 50a formed in sequence. The TFT array substrate 2 has a TFT, a pixel electrode 22, and a lower alignment film 50b formed in sequence.
The TFT of the TFT array substrate 2 includes: a gate electrode 6 connected to a gate line; a source electrode 8 connected to a data line; and a drain electrode 10 connected to the pixel electrode 22 through a drain contact hole 26. The TFT further includes a semiconductor layer 14 to generate a conductive channel between the source electrode 8 and the drain electrode 10 when a gate voltage is applied to the gate electrode 6. The semiconductor layers 16 provide a low resistance contact between the semiconductor layer 14 and each of the source and the drain electrodes 8 and 10. The TFT selectively feeds a data signal from the data line (not shown) to the pixel electrode 22 in response to a gate signal from the gate line (not shown).
The pixel electrode 22 is located in a pixel region that is defined by the data line and the gate line, and is made of a transparent conductive material having a high light transmissibility. The pixel electrode 22 is formed on a protective film 18 that is over the entire surface of the lower substrate 1. The pixel electrode 22 is electrically connected to the drain electrode 10 through the drain contact hole 26 in the protective film 18. A potential difference is generated between the pixel electrode 22 and the common electrode 48, which is formed on the upper substrate 42, when a data signal is fed to the pixel electrode 22 by way of the TFT. Due to the dielectric anisotropy of the liquid crystal molecules 52, the potential difference causes a rotation of the liquid crystal molecules 52 located between the lower substrate 1 and the upper substrate 42. Because the liquid crystal molecules 52 can be rotated, the quantity of light transmitted from a light source to the upper substrate 42 by way of the pixel electrode 22 can be regulated.
The black matrix 44 of the color filter array substrate 4 is formed to overlap the TFT, the gate lines (not shown), the data lines (not shown) of the lower substrate 1, and to define a pixel region where the color filter 46 will be formed. The black matrix 44 serves to prevent light leakage while absorbing external light, thereby achieving an increase in the contrast ratio. The color filter 46 is formed in the pixel region defined by the black matrix 44. The color filter 46 includes red, green, and blue color filters, to enable emission of light of red, green, and blue colors. The overcoat layer 47 is formed by applying transparent resin, having an insulation property, on the upper substrate 42 after the color filter 46 is formed on the upper substrate 42. The overcoat layer 47 serves to electrically insulate the black matrix 44 from the common electrode 48 to which a common voltage is applied. In the alternative, the overcoat layer 47 may be omitted in TN-mode devices.
A potential difference is generated between the pixel electrode 22 and the common electrode 48, which has a common voltage applied thereto, when a data signal is fed to the pixel electrode 22 by way of the TFT. The common voltage can be a reference voltage for reorientation of the liquid crystal molecules 52. In the case of IPS mode devices, the common electrode is formed on the lower substrate 1 rather than the upper substrate 42.
The upper and lower alignment films 50a and 50b for use in the initially alignment of liquid crystal molecules 52 are formed on the color filter array substrate 4 and the TFT array substrate 2, respectively, by applying an alignment material, such as polyimide (PI), onto the pixel electrode 22 and the common electrode 48, and then, performing a rubbing process.
A method for manufacturing the liquid crystal panel includes a photoresist (hereinafter, referred to as “PR”) patterning process, an etching process, and a PR pattern stripping process, which are used in either patterning electrodes or forming contact holes. Also, a washing process can be performed prior to or after performing one or more of the above described processes. The PR patterning process, etching process, and PR pattern stripping process are used for the formation of color filters and the patterning of electrodes as well as in the manufacture of TFTs. The etching process, PR pattern stripping process, and washing process are spraying processes, and therefore, these spraying processes are performed by use of a spraying apparatus that is designed to inject a chemical material or de-ionized (DI) water onto a substrate using spray nozzles.
FIG. 2 is a schematic view illustrating a related art spraying apparatus. As shown in FIG. 2, the related art spraying apparatus includes a substrate 60, a pipe 70 positioned over the substrate 60, a tube 72 for supplying fluid into the pipe 70, and a plurality of spray nozzles 80 mounted on the pipe 70 for spraying fluid supplied into the pipe 70 onto the substrate 60. The fluid, which is supplied into the pipe 70, is either a chemical material for etching or stripping a pattern on the substrate 60, or de-ionized water for washing the substrate 60. The pipe 70 is mounted parallel to either a longer or shorter side of the substrate 60 at a predetermined height above the substrate 60. The fluid is supplied at a predetermined pressure from an external tank (not shown) into the pipe 70 by way of the tube 72.
FIG. 3 is a view illustrating a spray nozzle of FIG. 2. As shown in FIG. 3, each of the plurality of spray nozzles 80 is formed with an injection hole 81 having a circular cross-section. The injection hole 81 is used to inject the fluid, which is supplied from the pipe 70, onto the substrate 60 at a predetermined injection angle and with a predetermined injection pressure.
The related art spraying apparatus having the above described configuration is able to inject the fluid onto the substrate 60 through the injection holes 81 formed in the plurality of spray nozzles 80, thereby etching or stripping a pattern formed on the substrate 60, or washing the substrate 60. To achieve a uniform pattern etching or stripping effect during the etching or pattern stripping process, the injection angle of the spray patterns for the plurality of spray nozzles 80 can not be concentrated and the spray patterns should overlap without each other. Similarly, to uniformly wash a substrate, the injection angle of the spray patterns for the plurality of spray nozzles 80 can not be concentrated and the spray patterns should overlap with each other. Further, to prevent damage to the substrate, the injection pressure of the injected fluid impacting the substrate can not be too strong. Thus, the injection angle and the injection pressure of the fluid must be regulated.
In the case of the related art spraying apparatus, both the injection angle and the injection pressure of the injected fluid are determined in accordance with the shape and size of the injection holes 81 that are formed in the plurality of spray nozzles 80, and to some extent, by the height of the nozzles above the substrate and the pressure within the pipe. Thus, the injection angle and the injection pressure can not be easily regulated for different fluids or for spraying processes injecting fluids at different injection pressures. Typically, a different pipe with different nozzles are used for different fluids. Further, minor variations amongst the plurality of nozzles causes the entire pipe having a plurality of spray nozzles to be adjusted for the worst performing spray nozzle on the pipe.